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Homework Statement
simplify (2x-3)² - 2x(2x-5).
Homework Equations
The Attempt at a Solution
(2x-3)² - 2x(2x-5)
to
2x² + 9 - 4x² + 10x
to
2x² + 9 + 10x
thanks, the whole time i was staring at the (2x-3)² and was just thinking about how wrong i was doing it, i always forget that double bracket thing when it comes to these situations, just dont get these muchhi tehmatriks!
sorry, but your (2x-3)² is completely wrong
if you can't do it in your head, write it as (2x-3)(2x-3) first, and then expand it
Use = between expressions that have the same value.thanks, the whole time i was staring at the (2x-3)² and was just thinking about how wrong i was doing it, i always forget that double bracket thing when it comes to these situations, just dont get these much
thanks again man, here's the final result
(2x-3)² - 2x(2x-5)
to
(2x-3)(2x-3) - 2x(2x-5)
to
4x - 6x - 6x + 9 - 4x + 10x
to
9 - 2x
dammit, it's always the simplest of things that i forgetUse = between expressions that have the same value.
(2x-3)^{2} - 2x(2x-5)
= (2x-3)(2x-3) - 2x(2x-5) -- so far, so good
After that, things go downhill.
(2x)(2x) = 2*2*x*x = ?
And -2x(2x - 5) = -2x * 2x -2x * (-5) = ?
You have to distribute the -2x over both terms inside the parentheses.